Percussion tool



April 23, 1968 A. MARTINI PERCUSSION TOOL m A f 5 Sheets-Sheet l FlO. `l

, Filed May 25, 1966 @gli INVENTOR Leo A. Martini ATTORNEYS INVENTOR 5 Sheets-Sheet 2 ATTORNEYS priZS, 1968 l.. A. MARTlNl PERCUSSION TOOL Filed May 23, 1966 saw,

Leo A. Martini FIG.7

pri 23, 1968 L.. A. MARTINI PERCUSSION TOOL 5 Sheets-Sheet 3 Filed May 255, 1966 74 S w Y W, 2 m W f XT m ELI. n MUN m Q m G M. f DI.. A O e Lf Y l B G W I El Ky f v9 w f O 4. ma .wf l. G 3 f4 2 :l K El D M. I y N www MwQMm/,w ZM a M United States Patent O 3,379,261 PERSUSSIN TOOL Leo A. lvlartini, 2623 Hudnall, Apt. 212, Dalias, rEen. 75235 Filed May 23, 1965, Ser. No. 552,219 6 Claims. (Cl. 173-64) rl`his invention relates to new and useful improvements in percussion tools for drilling wells and more particularly to automatic cycling means and the use of the inertia or kinetic energy of hydraulic means to provide greater drilling energy at the drill bit by utilizing the momentum of a moving column of weighted drilling fluid to impart to said bit downward impacts at a high rate of speed in addition to the normal boring action of said bit.

The primary object of this invention is to provide a novel tool for increasing drill penetration rates by exerting downward impacting action to a drill bit in addition to its conventional rotation.

Other objects of the invention are to provide a novel percussion tool for increasing the penetration rate of a drill bit by utilizing the inertia or kinetic energy stored in a column of weighted drilling iluid by virtue of its mass and velocity; to provide a novel percussion tool for applying energy directly to a drill bit by hydraulic means instead of by mechanical means at the surface; to provide a novel percussion tool that releases sufficient energy to continue drilling with a dull drill bit long after conventional drilling becomes ineicient; to provide a novel percussion tool that extends the life of the drill bit used per foot of hole drilled because less drill collar weight is required to be continuously applied to said bit and due to the very short duration of the impact force which is applied to said bit; to provide a novel percussion tool that permits the use of more economical and longer life bits of solid, tishtail or carbide button type without sacrificing penetration rates: to provide a novel percussion tool for drilling straighter bore holes by employing the pendulum technique of hanging more of the drill string weight while maintaining greater penetration rates; to provide a novel percussion tool that will more etectively clean cuttings from the bottom of a bore hole by supplying pulsating drilling uid to a drill bit; and to provide a novel percussion tool that is operable by the pressure of drilling fluid and utilizes the kinetic effect of abruptly halting a moving column of lluid to produce a very rapid percussive blow.

Additional objects of the invention are to provide a novel percussion tool capable of producing a high rate of impacts per minute as well as rapid impacts at substantially the speed or" sound; that is compatible with conventional drilling equipment; that permits reverse circulation of drilling fluid whenever necessary; that permits draining and lilling of the drill pipe automatically during installation in and removal from a fluid-filled borehole; that is completely automatic in operation; that is especially adapted for drilling hard formations while maintaining better penetration rates; that is lubricated internally by the drilling iluid or otherwise and is of durable, relatively simple construction; that raises the energy level over other types of impact tools and to such a degree that the hardest formations can be penetrated at greater speed; that utilizes the basic laws of hydrodynamics and motion to create a dynamic torce or fluid hammer for drilling boreholes; and that has relatively fast valve closure and cycles of operation for delivering up to 400G percussive blows of increased magnitude per minute.

A construction designed to carry out the invention will be hereinafter described, together with other features of the invention.

The invention will be more readily understood from a 3,379,26l Patented Apr. 23, 1968 reading of the following specification and by reference to the accompanying drawings, wherein examples of the invention are shown, and wherein:

FIG. l is a side elevational view of a portion of a drill pipe disposed in a well bore and having a percussion tool, constructed in accordance with the invention, mounted therein above its drill bit,

FIG. 2 is an enlarged, transverse, vertical, sectional view of the upper portion of the percussion tool and a portion of the drill pipe, showing said tool at rest,

FIG. 2-A is a continuation of FIG. 2, showing the lower portion of the tool and a portion of the drill bit,

FIG. 3 is a horizontal, cross-sectional view taken on the line 3-3 of FIG. 2,

FIGS. 4, 5 and 6 are horizontal cross-sectional views taken on the lines L -4, 5-5 and 6 6, respectively, of FIG. 2-A,

FIG. 7 is a transverse, vertical, sectional view of the tool in its impact or driving position and with its control valve closed,

FIG. 8 is a view, similar to FIG. 7, showing the upper portion of the tool immediately after impact,

FIG. 9 is a View, similar to FIG. 7, showing full opening of the control valve of the tool after impact,

FIG. l() is a view, partly in elevation and partly in section, of the lower portion of the tool with its low restricting valve in open position,

FIG. 11 is a view, similar to FIG. 10, showing a modiiication,

FIG. 12 is a horizontal, cross-sectional view taken on the line 12-12 of FIG. l1,

FIG. 13 is a View, partly in elevation and partly in section, showing a modified connection of the driver sub of the tool, and

FIG. 14 is a perspective View of the spring of the llow restricting valve.

In the drawings, the numeral 10 designates the elongate, cylindrical casing or tubular housing of a percussion drilling tool having a coupling or sub 11 screwthreaded in its upper end for screwthreaded connection with the lower drill collar 12 of a rotary drill pipe or stem. A conventional rotary drill bit 13, of any suitable type, is screwthreaded in the lower end of a driver sub or coupling 14 which has splined connection with the lower end of the housing 10, the sub having external splines 15 extending longitudinally thereof and said housing having internal splines 16 complementary to and coacting with the external splines (FIGS. 2-A and 6). Above the splines 15, the driver sub 14 has its upper end reduced and screwthreaded in the lower end of a cylindrical valve cage -17 which has its upper end reduced and screwthreaded in the lower end of an elongate, tubular barrel or sleeve 18 extending to the upper end portion of the housing and terminating below the upper sub 11 (FIG. 2). A cap 19 is screwthreaded in and closes the upper end of the barrel 18.

The upper portion of the valve cage 17 and the entire barrel are of less diameter than the bore of the housing 14 to provide an annular ow space Ztl therebetween which communicates with the drill pipe through the sub 11 and collar 12, whereby weighted drilling fluid or mud is conducted around said barrel to the intermediate portion of said cage. As shown most clearly in FIGS. 2-A and 5, radial ports 21 yare formed in the intermediate portion of the valve cage to permit the drilling fluid in the annular space 20 to ow into said cage and downwardly therefrom through the driver sub 14 to the drill bit 13. From the drill bit, the drilling tlui-d flows upwardly through the well bore `and around the drill pipe tand impact tool in the usual manner. The lower portion of the valve cage 17 is enlarged so as to be of substantially the same diameter as the bore of the housing and carries suitable external packing 22 for sealing olf therebetween. A packing ring 23 is also interposed between the cage and driver sub immediately below their screwthreaded connection.

For controlling flow through the driver sub 14, an annular, bevelled, upwardly-facing valve seat 24 is formed in the upper end of said sub and is adapted to be engaged by an annular, substantially spherical valve member or ead 25 which is screwthreaded on the lower end of an elongate, tubular mandrel 26. Inserts 27 and 28, of polyurethane or other suitable elastic material, overlie the valve seat 24 and the lower portion of the valve head 25 to prevent fluid erosion thereof yand provide a positive seal therebetween. The mandrel 26 extends throughout the major portion of the barrel 18 and terminates below the upper end thereof (FIG. 2) so that the bore of said mandrel establishes communication between the upper portion of said barrel and the valve cage 17, when the valve head is unseated, yas well as the bore of the driver Sub.

A piston assembly P is reciprocably mounted in the bore of the barrel 18 in surrounding relation to the mandrel for slidably supporting the same and is adapted to rest on Aan annular shoulder 29 formed by the upper end of the valve cage 17. The piston 4assembly P includes annular lower and upper heads or portions 30 and 31 screwthreadedly connected by a cylindrical sleeve 32 upstanding from the lower piston head 30 in spaced concentric relation to the mandrel 26. Each piston head is of substantially the same radial width as the space between the barrel bore and mandrel and carries suitable external .and internal packing 33 and 34 at its outer end for sealing off around the piston head and around the mandrel. An annular retainer or lat ring 35 overlies the outer end surface of each piston head and is secured thereto by screws 36 for conning the packing 33 and 34 against displacement.

A `helical spring 37 is confined within the sleeve 32 of the piston assembly P for underlying engagement with an annular enlargement or head 38 formed externally on the upper, intermediate portion of the mandrel 26 and having ribs 39 extending longitudinally thereof (FIGS. 2 and 3). The spring 37 rests on an annular, internal shoulder 40, formed by the upper or inner end surface of the lower piston head 30, and constantly urges the mandrel head 38 into engagement with a similar shoulder 41 formed by the lower or inner end surface of the upper piston head 31, whereby the mandrel 26 is resiliently supported by said spring with the valve Y head 25 spaced from the valve seat 24 (FIG. 2A). Since downward movement of the piston assembly is prevented by the shoulder 29, partial compression of the spring is required in order for the valve head to seat as shown in FIG. 7. A helical spring 42 is confined within the upper end of the barrel 18 between the cap 19 and the upper or outer end surface of the upper piston head 31 for resiliently maintaining the lower or outer end surface of the lower piston head 30 in engagement with the shoulder 29 whereby the piston assembly P cannot move upwardly until the spring is compressed.

For controlling the reciprocation of the piston assembly, an annular, bevelled, downwardly-facing valve seat 43 is formed within the valve cage 17 above its ports 21 on the lower end of a reduced bore portion 44 of relatively short length and having an inwardly and downwardly bevelled shoulder 45 at its upper end. An annular valve element or collar 46, of less diameter than the reduced bore portion 44 and of greater diameter than the mandrel 26, is suspended concentrically within said bore portion by an annular spring 47 which has its outer periphery bearing against the shoulder 45 as well as the bore of the valve cage. The valve collar 46 extends through the reduced bore portion and has an outwardlyllared llange or seating surface 48 depending from its lower end for complementary, underlying engagement with the seat 43. A seating ring 49, of suitable elastic material, is carried by the llange 48 for sealin g off between the valve seat and flange, As shown most clearly in FlG. 14, the spring 47 is arched or bowed upwardly and inwardly and has internal, radial prongs or projections 5G for recessed engagement with the upper end portion of the valve collar (FIG. 2-A) so as to constantly urge said collar upwardly and resiliently maintain its flange in engagement with the seat 43 to prevent flow around said collar. Except for its pron-gs 59, the internal periphery of the spring is spaced from the valve collar 46 (FIG. 4) to permit tlow therearound when said spring is exed downwardly to disengage the flange 48 of said collar from the valve seat. Since the bore of the valve collar is spaced from the mandrel 26, there is constant limited communication through said collar.

When the percussion tool is at rest or inoperative, the valve head 25 is spaced from the valve seat 24 in an intermediate position due to the torce of the spring 42 holding he lower head 3() of the piston assembly P in engagement with the shoulder 29 and the force of the spring 37 holding the head 39 of the mandrel 26 in engagement with the shoulder 41 (FIG. 2). This intermediate position of the valve head permits restricted ow of drilling fluid from the valve cage 17 downwardly' through the valve seat and the bore of the driver sub 14 to the drill bit 13. Also, the drilling fluid is free to flow upwardly through the bore of the tubular mandrel into the barrel 18 above the piston assembly. Due to the aforesaid llow restriction, the continued circulation of drilling fluid causes the pressure within the valve cage to increase sufficiently to force the valve head into engagement with its seat by partially compressing the spring 37 (FIG. 7). The seating of the valve is rapid since its closing movement increases the tlow restriction so as to increase the pressure differential across the valve seat 24. At the moment of valve closure, the entire column of fluid moving downwardly through the drill pipe above the valve is abruptly halted and the inertia or kinetic energy of said moving column, by virtue of its mass and velocity, rapidly impacts against the driver sub 14 through its closed upper end as well as against the upwardly -facing surfaces of the valve cage 17 and barrel 18. This sudden impact is at substantially the speed of sound and forces the valve cage, housing and driver sub downwardly relative to the housing 10 so as to transmit a percussive blow to the drill bit for driving its cutters into the formation and thereby increasing the effectiveness of said bit.

Simultaneous with the valve closure, the increased pressure of the fluid within the valve cage 17 causes said lluid to low upwardly between the mandrel 26 and valve collar 46 into the barrel 1S below the piston assembly P. Since the ange 48 of the valve collar is exposed to this pressure, said lange is held in engagement with the seat 43 to prevent upward flow around said collar. Accordingly, the upward flow of lluid is .restricted to the bore of the valve collar 46 and allows sufficient time for the formation to receive the full impact of the blow before the valve head 25 reopens. The pressure of the fluid below the piston assembly forces said assembly upwardly so as to partially compress the spring 42 thereabove and fully compress the spring 37 therein (FIG. 8), the valve head being exposed to the pressure of the fluid within the valve cage so as to be held in engagement with the valve seat 24 as shown in FIG. 7. Since the bore of the mandrel is in constant communication with the bore of the driver sub 14 and the space within the barrel above the piston assembly P, the fluid in said space is discharged through said mandrel to said driver sub.

After complete compression of the spring 37, the piston assembly continues to move upwardly and lifts the valve head 25 from its scat due to the fact that said assembly is of greater area than said valve head. This partial unseating of the valve head reduces the pressure differential across the valve seat 24 and permits the force of the compressed spring 37 to lift the mandrel head 39 into engagement with the shoulder 41 of the piston assembly whereby said valve head jumps to its uppermost position and allows full fluid flow through said valve seat (FIG. 9). With full fluid flow, the pressure within the valve cage and below the piston assembly P is reduced whereby the force of the spring 42 urges said assembly downwardly into engagement with the shoulder 29. Due to the restricted opening through the valve collar 46, this downward movement increases the pressure between the piston assembly and valve collar and is exerted against said collar so as to unseat its ange 48 and permit flow around as well as through said collar whereby said downward movement is rather rapid. The valve head 2S and Inandrel 26 move downwardly with the piston assembly to the position shown in FIG. 2-A and the spring 47 reseats the flange of the valve collar upon equalization of the pressure thereacross. The tool is now in condition for the next cycle of operation which is repeated continually. It has been found that the cycles of operation can occur effectively at the rate of 4000 per minute.

In some instances, it is necessary to continue the ow of drilling uid to the drill bit 13 when the valve head 25 is seated as shown in FIG. 2-A. Suficient velocity of ow must be maintained in the well bore to lift the cuttings therethrough around the drill pipe. Another reason for continued ow may be the necessity of reducing the magnitude of the percussive blows imparted to the formation by the tool in order to prevent the creation of excessive forces. As shown in FIGS. 1l and 12, small lateral ports 51 may be formed in the mandrel 26 above the valve head to permit limited ow of uid through said valve head when said valve head is seated. It is noted that the combined areas of the ports 51 are insufficient to accommodate the entire flow whereby said ports do not interfere with the opening and closing of the valve head and the imparting of rapid percussive blows by reciprocation of the driver sub 14.

When the drill pipe is of great length, such as in deep wells, said pipe has sufficient elasticity to eliminate the necessity for reciprocation of the driver sub. 'Upon interruption of the ow of the drilling fiuid resulting from seating of the'valve head 25, the inertia or kinetic energy of the moving column of fluid is adequate to elongate a long string of drill pipe and thereby cause impacting of the tool. Instead of the slidable connection provided by the splines 15 and 16, the tool has the lower end of its housing 10 screw-threaded onto the upper portion of a modified driver sub 52 as shown in PIG. 13. The upper extremity of the modified sub 52 is screwthreaded into the lower end of the valve cage 17 in the same manner as the driver sub 14 and the other parts remain the same except for the omission of the unnecessary packing 22.

The foregoing description of the invention is explanatory thereof and various changes in the size, shape and materials, as well as in the details of the illustrated construction may be made, within the scope of the appended claims, without departing from the spirit of the invention.

What I claim and desire to secure by Letters Patent is:

1. A percussion tool for a rotary drill bit mounted on the lower end of a rotary drill pipe including a housing connected in the drill pipe adjacent the drill bit and having a passage for conducting drilling fluid from said pipe to said bit, an upwardly facing valve seat at the lower portion of the passage of the housing, a valve member in said housing passage above the valve seat and movable by the flow of the drilling uid through said passage into engagement with said seat to halt said ow whereby the inertia of said fluid imparts a downward impact to said drill bit, a tubular barrel mounted in said passage above said valve seat in spaced relation to said housing and having a closed upper end and an open lower end communicating with said passage, a piston reciprocably mounted in the barrel and having its lower end exposed to the fluid in said passage whereby the piston is movable upwardly by the pressure of said fluid when the valve member is seated, stop means in said barrel underlying said piston, first resilient means for urging said piston downwardly into engagement with the stop means, a mandrel upstanding from said valve member so as to be movable therewith and slidably supported by said piston whereby said valve member is unseated by upward movement of said piston, second resilient means between portions of the mandrel and piston for supporting said mandrel in coaction with said piston, the second resilient means urging said mandrel upwardly relative to said piston to unseat said valve member and permitting relative downward movement of said mandrel and seating of said valve member, said second resilient means being compressed by upward movement of said piston relative to said mandrel whereby said valve member remains seated during initial upward movement of said piston, and spring pressed upwardly seating valve means at the lower end of said barrel in surrounding relation to said mandrel for restricting the upward fiow of iiuid from said passage into said barrel to retard upward movement of said piston and unseating of said valve member and for permitting substantially unrestricted downward iiow from said barrel to said passage upon unseating of said valve member whereby said piston is rapidly reengaged with said stop means by the force of the rst resilient means.

2. A percussion tool as set forth in claim 1 wherein the valve means includes an opening for permitting the restricted upward flow of fluid from the passage of the housing into the barrel and for coacting with the unseated value means to permit the substantially unrestricted downward flow from said barrel to said passage.

3. A percussion tool as set forth in claim 1 wherein the valve means includes a downwardly facing valve seat and an annular spring pressed valve element engageable with the downwardly facing valve seat.

4. A percussion tool as set forth in claim 3 wherein the valve element is spaced from the mandrel to provide an opening for permitting the restricted upward flow of fluid from the passage of the housing into the barrel and for coacting with the unseated valve element to permit the substantially unrestricted downward flow from said barrel to said passage.

5. A percussion tool as set forth in claim 1 wherein the mandrel is tubular and extends through the valve member and piston to establish communication between the passage of the housing and the portion of the barrel above the piston.

6. A percussion tool as set forth in claim 5 wherein the tubular mandrel has a lateral opening in constant communication with the passage of the housing to permit a partial flow of drilling fluid from said passage through said mandrel to the drill bit when the valve member is seated.

References Cited UNITED STATES PATENTS 2,580,203 12/1951 Topanelian 175-296 X 2,837,317 6/1958 Hulshizer 173--17 2,851,251 9/1958 Mori 175-296 X 3,038,548 6/1962 Brown 175-296 X 3,059,619 10/1962 Beaumont 173-64 CHARLES E. OCONNELL, Primary Examiner.

NILE C. BYERS, JR., Examiner. 

1. A PERCUSSION TOOL FOR A ROTARY DRILL BIT MOUNTED ON THE LOWER END OF A ROTARY DRILL PIPE INCLUDING A HOUSING CONNECTED IN THE DRILL PIPE ADJACENT THE DRILL BIT AND HAVING A PASSAGE FOR CONDUCTING DRILLING FLUID FROM SAID PIPE TO SAID BIT, AN UPWARDLY FACING VALVE SEAT AT THE LOWER PORTION OF THE PASSAGE OF THE HOUSING, A VALVE MEMBER IN SAID HOUSING PASSAGE ABOVE THE VALVE SEAT AND MOVABLE BY THE FLOW OF THE DRILLING FLUID THROUGH SAID PASSAGE INTO ENGAGEMENT WITH SAID SEAT TO HALT SAID FLOW WHEREBY THE INERTIA OF SAID FLUID IMPARTS A DOWNWARD IMPACT TO SAID DRILL BIT, A TUBULAR BARREL MOUNTED IN SAID PASSAGE ABOVE SAID VALVE SEAT IN SPACED RELATION TO SAID HOUSING AND HAVING A CLOSED UPPER END AND AN OPEN LOWER END COMMUNICATING WITH SAID PASSAGE, A PISTON RECIPROCABLY MOUNTED IN THE BARREL AND HAVING ITS LOWER END EXPOSED TO THE FLUID IN SAID PASSAGE WHEREBY THE PISTON IS MOVABLE UPWARDLY BY THE PRESSURE OF SAID FLUID WHEN THE VALVE MEMBER IS SEATED, STOP MEANS IN SAID BARREL UNDERLYING SAID PISTON, FIRST RESILIENT MEANS FOR URGING SAID PISTON DOWNWARDLY INTO ENGAGEMENT WITH THE STOP MEANS, A MANDREL UPSTANDING FROM SAID VALVE MEMBER SO AS TO BE MOVABLE THEREWITH AND SLIDABLY SUPPORTED BY SAID PISTON WHEREBY SAID VALVE MEMBER IS UNSEATED BY UPWARD MOVEMENT OF SAID PISTON, SECOND RESILIENT MEANS BETWEEN PORTIONS OF THE MANDREL AND PISTON FOR SUPPORTING SAID MANDREL IN COACTION WITH SAID PISTON, THE SECOND RESILIENT MEANS URGING SAID MANDREL UPWARDLY RELATIVE TO SAID PISTON TO UNSEAT SAID VALVE MEMBER AND PERMITTING RELATIVE DOWNWARD MOVEMENT OF SAID MANDREL AND SEATING OF SAID VALVE MEMBER, SAID SECOND RESILIENT MEANS BEING COMPRESSED BY UPWARD MOVEMENT OF SAID PISTON RELATIVE TO SAID MANDREL WHEREBY SAID VALVE MEMBER REMAINS SEATED DURING INITIAL UPWARD MOVEMENT OF SAID PISTON, AND SPRING PRESSED UPWARDLY SEATING VALVE MEANS AT THE LOWER END OF SAID BARREL IN SURROUNDING RELATION TO SAID MANDREL FOR RESTRICTING THE UPWARD FLOW OF FLUID FROM SAID PASSAGE INTO SAID BARREL TO RETARD UPWARD MOVEMENT OF SAID PISTON AND UNSEATING OF SAID VALVE MEMBER AND FOR PERMITTING SUBSTANTIALLY UNRESTRICTED DOWNWARD FLOW FROM SAID BARREL TO SAID PASSAGE UPON UNSEATING OF SAID VALVE MEMBER WHEREBY SAID PISTON IS RAPIDLY REENGAGED WITH SAID STOP MEANS BY THE FORCE OF THE FIRST RESILIENT MEANS. 